possessed by a demon

Translations
одержимый демоном
He seemed possessed by a demon, acting in ways he never had before.
Он казался одержимым демоном, ведя себя так, как никогда раньше.
Definitions
Experiencing a state in which an individual is believed to be under the control or influence of a malevolent supernatural entity, often characterized by unusual behavior, loss of self-control, or other manifestations attributed to demonic influence.